In piston engines, intake gases are pulled into the cylinder by the downward stroke of the piston (which creates a low-pressure area). The amount of air which is actually pulled into the engine is often the limiting factor in the performance of the engine. In the past, to overcome the limitations of inadequate air supply, engines are equipped with turbochargers
The need to optimize the horsepower, efficiency, speed and acceleration of engines has motivated the development of many different turbocharger devices, including those known as turbochargers and others known in the field as superchargers. Both turbochargers and superchargers produce a boost in airflow and air pressure to the engine's combustion chamber(s), which results in a desired, although delayed, increase in horsepower, efficiency, speed and acceleration.
A turbocharger is known in the field to produce that boost in airflow by utilizing the flow of exhaust gases from the engine which, by various means, ultimately power (rotate) an impeller, which herein means a fan-like air pump/air compressor apparatus, in the turbocharger, which draws in outside air (at atmospheric pressure), and that may push and compress that air to higher than atmospheric pressure, and forces that outside air to the combustion chamber of an engine (including the engine's intake manifold). This increased airflow results in increased engine output (RPMS, acceleration, efficiency and horsepower). Thus, a turbocharger is exhaust gas driven, and not mechanically driven.
A supercharger is known in the field to produce a similar boost in airflow by mechanically utilizing power tapped from the engine by means of operably coupling to the engine to receive rotational motion, usually by means of a pulley or other similar device, which is connected to one of the pulleys, belts or belt systems at, or near, the front of the engine (these pulleys, belts, etc., being a transmission device, transferring power from the engine to the supercharger) to power (rotate) an impeller, twin-screw or other type of air pump, air-compressing device, which draws in outside air and forces or compresses that outside air to the engine's combustion chamber(s), with a similar result of increasing engine output (RPMS, acceleration, efficiency and power). Thus, a supercharger is mechanically driven, not exhaust driven.
A turbocharger may compress air that is supplied to the combustion chambers of an engine. In particular, a turbocharger may supply air at a higher pressure and higher density than would otherwise be possible. Thus, the objective of a turbocharger is to improve an engine's volumetric efficiency by increasing the density of the intake air. Stated another way, turbochargers allows engines to squeeze more air into a cylinder, which means that more fuel can also be added to the cylinder. Therefore, more power is produced from each explosion in each cylinder.
Most modern turbochargers include a turbine driven compressor. Typically, a turbocharger is bolted to the exhaust manifold. The exhaust from the cylinders spins the turbine. In particular, the exhaust spins the turbine as it passes through the blades of the turbine. The more exhaust that passes through the blades, the faster the turbine spins.
The turbine is connected by a shaft to a compressor, which is located between the air filter and the intake manifold. The compressor pressurizes the air going into the piston cylinders. The compressor is typically a type of centrifugal pump that draws air in at the center of its blades and flings it outwards as it spins.
The shaft that connects the turbine to the compressor will generally be surrounded by a thrust bearing and two (2) journal bearings. The purpose of these bearings is to control the x, y, and z motion of the shaft. However, the thrust bearing is the “weak link” in the turbocharger system. In fact, many thrust bearings have been known to “fail” (e.g., just continuously spin), thereby reducing and/or eliminating the effectiveness of the turbocharger.
For example, as the compressor wheel spins, a “boost pressure” is formed from the compressed air. As boost pressure develops, the pressure is exerted on the back side (the non-airfoil side) of the compressor wheel, causing a forward (axial) thrust. For example at 40 psi, on a 2.5 inch exducer compressor wheel, the forward thrust would be approximately 197 lbs of axial thrust. In turn, the compressor wheel acts likes an airplane propeller and tries to climb forward through the air, which increases the axial thrust. Moreover, in the event of surge (e.g., a situation where the compressor wheel changes direction of spinning due to air going backwards through the intake), the thrust load will be violently changed back and forth, also causing huge thrust loads.
It is these thrust loads (e.g., caused by the event of surge or the general thrust load caused by the axial thrust) that may ultimately cause the thrust bearing to fail. As the thrust bearing is generally a “weak link” in the turbocharger, there is a need in the art to replace the thrust bearing with a new, stronger device. Such a device is disclosed herein.
Another common area of failure in a turbocharger is the journal bearings. Excessive heat, speed, lack of lubrication can cause these journal bearings to fail, which is quite common.